


Improper Use of Force

by OnyxSinz (OnyxianDrake)



Series: Onyx's Drabbles [2]
Category: Undertale (Video Game)
Genre: Alpha Female, Alpha!Reader, Alpha/Beta/Omega Dynamics, Alpha/Omega, Alternate Universe - Underswap (Undertale), Aphrodisiacs, Begging, Biting, Bondage, Claiming, Claiming Bites, Crying, Crying During Sex, Date Rape Drug/Roofies, Dildos, Ecto-Genitalia (Undertale), Ecto-Vagina (Undertale), F/M, Female Reader, Non-Traditional Alpha/Beta/Omega Dynamics, Rape Fantasy, Rape Roleplay, Rape/Non-con Elements, Reader-Insert, Size Difference, Somnophilia, Strap-Ons, Underswap Papyrus (Undertale), Underswap Sans (Undertale), omega male, reader tops
Language: English
Status: Completed
Published: 2020-08-03
Updated: 2020-08-03
Packaged: 2021-03-05 21:28:28
Rating: Explicit
Warnings: Creator Chose Not To Use Archive Warnings
Chapters: 1
Words: 2,179
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/25692070
Author URL: https://archiveofourown.org/users/OnyxianDrake/pseuds/OnyxSinz
Summary: Blue was going to be yours, and there wasn't anything anyone could do to stop you.
Relationships: Sans (Undertale)/Reader
Series: Onyx's Drabbles [2]
Series URL: https://archiveofourown.org/series/1903180
Comments: 4
Kudos: 105





	Improper Use of Force

**Author's Note:**

> Please mind the tags, and I hope you enjoy!

Watching him sleep was a temptation in itself. Tied up and exposed, magic glowing and glistening where it was already warm and cushiony on his bones. The curve of his ass and the smooth ecto of his thighs was soft and pliant beneath your hands, all the more of a promise to the reward for your troubles.

Drugging him had been easy, just a simple slip of a dissolvable tablet into his drink. Such a sweet skeleton, to trust you unconditionally. His brother had been the challenge, such a protective Beta, wanting to keep little Omega Blue safe and unclaimed. It was sweet...and had been a major obstacle in your plans.

Now, he was right where you wanted. Innocent, exposed and completely under your control to do whatever you wanted. Which led to the fact he was tied up, naked and magic purposefully coaxed into existence. Blue wasn’t even awake yet to play, but you didn’t mind. You needed him ready for when he did wake up, it was easier that way for both of you.

Just the tiniest movement and sound had your eyes locked onto him, watching his face contort and scrunch as he fought to wake up. No doubt his sweet Omega instincts were wiggling in his soul, telling him something was off about what was happening, that an Alpha was too close for comfort with him being unclaimed and aroused.

That had been a mix of the sedative aphrodisiac you had given him, along with you coaxing a few touches here and there to make him form what you wanted. The scene alone made you itch to touch more, throw patience and consideration out the window. But no. You waited, and now it was paying off as Blue slowly blinked awake, eyelights hazy and confused.

Tugging at the bindings was useless, although he tried to for a moment, unable to get out of the position the silk rope kept him in. You didn’t want him hurt, oh no, you wanted quite the opposite. It was just going to take a little bit to make Blue realize what you wanted, and that you were getting it by the end of the night.

Stretch didn’t expect him home until tomorrow morning, afterall, and he’d already texted him good night.

“Sleep well, cutie?” You purred, leaning forward when Blue finally focused on you.

Another tug at the rope, hips wiggling slightly as he tried to adjust how he was bent over with his ass in the air.

“...w-what?” He slurred, eyes scrunching shut before he blinked a few times, whining faintly when he still couldn’t get out of the bindings.

“Did you sleep well?”

You couldn’t help but smile at his cuteness, the pale blush spreading across his cheeks as realization set in.

“Why...why am I naked?” He stuttered, flinching when you stood up, struggling to keep his gaze on you.

“For one, you look oh so delectable like this~” You giggled, tails gently tracing up his spine, from between his scapulae to his sacrum, cushioned by the soft blue magic that started at his ribs.

You watched as Blue shivered, trying to pull away from your touch unsuccessfully.

“Don’t- don’t touch me there,” He whimpered, tugging at the ropes again. “Please...please untie me (y/n)...”

A soft chuckle escaped you despite your best attempts, endeared by the sweet fact he still was so innocent. Untouched, but knowing of what you planned to do...maybe. Or maybe he was oblivious, and just knew that you shouldn’t touch him down there...not until he’s yours, at least.

Which you certainly planned to make him. He was unclaimed, without an Alpha...an Omega without an Alpha was free to take, given you knew how to get around certain safeguards. The main obstacle to most was family; many kept the Omegas close, protected and guarded until they decided to choose an Alpha they wanted to be with forever.

Getting through Stretch’s barriers and into Blue’s space had been your obstacle, and you’d long since wiggled your way past his protective gaze. Right under his nose, you stewed until you got Blue alone without Stretch’s suspicions. A terrible decision on his part, really, but one you had manipulated and cultivated in your favor.

“I think I’ll keep you like this for now,” You replied finally.

“W-why?”

Kneeling down and getting close to Blue’s face gave you a waft of his scent, stronger and more alluring. He flinched when you brushed your fingers over his cheek, rattling faintly.

“I need to make you mine before I let you go.”

His sockets grew wide, eyelights shrinking as he tugged harder at the bindings keeping him as your little prisoner.

“N-no! Let me go! P-please, (y/n)!” He wailed, harshly jolting away from your touch to his shoulder, so harshly in fact he fell onto his side.

It was a bad choice for him, making it harder to move, but it was fine to you, even rolling him onto his back so he really couldn’t go anywhere, and he was right where you needed him. Tears were building in his sockets as you kneeled on the bed beside him, ribs heaving with hiccupy breaths.

Blue didn’t even try to hide his neck from you, despite how much he seemed to be distraught over the idea of you claiming him. It made it easier, moving forward despite how he strained to stop you, unable to get your hands off his shoulders. He even made it easier, acting like he could strain to get away before you sank your teeth into his clavicle.

A sharp shriek rang in your ears as bittersweet magic oozed onto your tongue, easy to clean away briefly before you pulled back, looking at the round rows of teeth marks, claiming him as yours.

“Why?” Blue cried, hiccuping again. “You’re- you’re a nice person, this isn’t n-nice…”

“It will be, Blue,” You giggled softly, kissing his forehead. “I just have to get you back on your knees first~”

A small yelp slipped from the skeleton as you pulled him back into place, watching him struggle a second to get his face out from being squished against the bed. Despite his fear, the drug was still going in his magic, pussy still wet and ready in his pelvis.

“This- this still isn’t nice! L-letting me go would be,” He continued to ramble before ending with a whimper when you cupped his ass and squeezed.

“Just be patient, Blue,” You purred, 

You had plans. Marking Blue was the easy part, claiming him as your own, it was such a simple thing to be so amazingly respected by the world.

Your hand slid down his thigh slowly, drawing a shiver from him. It was so tempting to move straight to what you were eager for, finger dancing over the soft slit of his magic. But not yet, you had to be prepared as well, not wanting to hurt him for his first sweet time.

Moving away from the bed was almost painful, Blue’s scent dominating the room, making you want to take him immediately. Yet you had restraint to get prepared, unzipping the bag you had set aside for this very moment. Being a female Alpha had its setbacks, but there were ways to work around it easily enough. Not that you necessarily needed the strap on, there were other ways to spend time pleasuring your new little Omega, but you wanted to have fun with it.

Blue was crying by the time you were ready, but he wasn’t trying to struggle out of his bonds or off the bed, which was a step up from before. Unfortunately he tried to lurch away when you moved up behind him on the bed, although he didn’t move far.

“Relax, Blue~”

“I-I can’t! I-I don’t want this,” He hiccuped, whimpering sharply when you grabbed his hips, rubbing gentle and slow circles with your thumbs.

“But you’re so wet, cutie,” You purred, leaning down next to his skull, the dildo you attached pressing hard against his soft magic. “You’re obviously enjoying this, even if you don’t want it~”

“That-that’s not-”

Blue squealed when you pulled back just enough to press the tip against him, slowly continuing to press until it popped in. It was up to your imagination for how he would’ve felt, so small and no doubt tight and warm. It left him breathless and unable to work up the effort for words, lost to small cries and moans the further the dildo slipped in.

Your draped your body over his back when it was all the way in, pressing soft kisses along his neck, “You’re being such a good boy~”

Blue inhaled sharply and let out a shaky moan, closer to a whimper, but you’d take what you could get. You knew the dildo was just a little too big for your small, newly claimed mate, but it was a better way to use his sensitivity to your advantage.

Pulling back out slowly had Blue tensing in expectation of pain, only for a choked moan to escape when he discovered it made it all the more intense for him. It was amusing, knowing the little virgin beneath you would know only what you’d give him, teaching him how it felt to be your mate for the rest of his life.

You couldn’t play gentle anymore, your own eagerness getting ahead of you before you were barely halfway pulled out. When your hips met his with a sharp thrust, a yelp slipped from between his teeth. From there you started a hard, quick pace, listening to the wet noises where you were connected and the high, beautiful notes being wrenched from the small skeleton beneath you.

Blue was still crying, hiccuping and whimpering between moans and sometimes a wail of pleasure when you hit that perfect little spot inside him, but he wasn’t fighting anymore. Hell, when you paid attention, it seemed like he was pressing back into you when you tried to pull out to give another bruising thrust.

“Aren’t you the perfect Omega,” You purred, feeling him shudder. “I bet you’re close…”

His only response was a soft whimper, turning a little sharper at the end when he felt your hand on his chest, tracing down his sternum to his abdomen. His trembling only increased as your hand crept closer between his legs, unable to close them.

“P-please,” He hiccuped quietly, gasping sharply when you just barely brushed your fingers over his clit.

“Please what?”

A chuckle escaped you when all he could give was a strangle whine, his voice trailing into a harsh moan when you circled his clit a little more firmly. Blue devolved back into pitiful mewls and noises of pleasure, body finally giving in and rocking with your thrusts. The movement had gentled with the distraction, but were easily brought back to making him yip and moan sharply with each one that hilted inside him, rocking him into the bed.

When he pressed up, tried arching further with the thrusting you knew he was getting close, moans turning to breathless pants and barely audible whimpers. His sweet face was scrunched up, focused on the pleasure and lost to the haze it provided. Grinning, all it took was a soft pinch for his sockets to fly wide open, breath stuck in his throat as he went stiff.

You didn’t stop there, watching his sockets brim with tears from the sensitivity of his first orgasm leading into the continuous overstimulation. You took back up you previous pace, his cries and moans music to your ears. You didn’t plan to stop until you were too tired to continue.

You had to show your new Omega the sweetness of being your mate, after all.

Blue was slow to come to after his final orgasm left him unconscious, but you were thankful all the same when he began to stir. A soft moan slipped from him as he woke up, pressing into your hands where you were massaging his shoulders.

“That was a lot,” Blue mumbled, purring softly when you leaned down and kissed his skull.

“Was it too much?”

“No,” He replied quickly, cheekbones blooming that adorable baby blue color of his magic. “It was...great.”

“I’m glad you liked it,” You giggled, pulling the small skeleton into your lap now, nuzzling and meeting him in a soft kiss.

“It was well worth the wait,” Blue sighed softly, nuzzling under your chin and tucking himself against your body. “I’m your Omega now! You’re stuck with me.”

That startled a soft laugh from you, Blue’s own giggles escaping him until you both quieted again. Blue was purring as you idly traced his ribs, relaxing in the bed with him in your lap. It had been well worth the planning for that scene, to result in the fact the Omega in your lap was all yours now. Nobody could take him.

Although, when Stretch finds out, you might not have very long to celebrate it.

**Author's Note:**

> I draw too ;)  
> Twitter: https://twitter.com/UnholyLiar


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